<ExtensionAttribute()>
Public Overloads Shared Function Where(Of TSource)( _
   ByVal source1 As IEntityQuery(Of TSource), _
   ByVal predicate As Expression(Of Func(Of TSource,Boolean)) _
) As IEntityQuery(Of TSource)

Dim source1 As IEntityQuery(Of TSource)
Dim predicate As Expression(Of Func(Of TSource,Boolean))
Dim value As IEntityQuery(Of TSource)
 
value = EntityQueryExtensions.Where(Of TSource)(source1, predicate)

[ExtensionAttribute()]
public static IEntityQuery<TSource> Where<TSource>( 
   IEntityQuery<TSource> source1,
   Expression<Func<TSource,bool>> predicate
)

[ExtensionAttribute()]
public:
static IEntityQuery<TSource^>^ Wheregeneric<typename TSource>
( 
   IEntityQuery<TSource^>^ source1,
   Expression<Func<TSource^,bool>^>^ predicate
) 

var mgr = new DomainModelEntityManager();

var query = mgr.Customers.Where(c => c.Country == "UK");
var list = query.Execute();